Leena Ali Mohamed , Sawsan Naguib Abdelbary And Dalia Hussein El-Rouby,

ABSTRACT
The Influence Of Sun Exposure, Gravity, And Years Of Facial Muscle Movements Starts To Appear As Wrinkles On The Skin Hyaluronic Acid Injection Can Be Used As A Dermal Filler To Improve The Skin?s Contour And Reduce Depressions In The Skin. The Present Work Aimed To Examine The Histopathological Changes Occurring In Lower Lip Of The Rats, As A Result Of HA Injection And Whether It Could Really Bring Us Closer To The ? Ideal Soft Tissue Filler Material ?. To Fulfill This Aim, Lip Sections Of Rats Treated With HA At Various Intervals Were Histologically Examined Using (H&E Stain), In Addition To Histochemical Examination Using (Masson?s Trichrome & Toluidine Blue Stain) And Immunohistochemical Analysis, Using CD68 Antibody. The Study Was Conducted On Thirty-six Adult Male Rats With Age Ranging From 2 To 3 Months And Weight Ranging From 150-200g. They Were Divided Into Two Groups, Each Consisting Of 18 Rats, The First Group Represents The Control Group I And The Second Group Represents The Experimental Group II. Each Group Was Subdivided Into Three Subgroups, According To The Time Of Sacrifice With Intervals Of 7 Days, 45 Days And 90 Days Following Injection As Group I A, B And C And Group II A, B And C Respectively. In Experimental Group II, Each Rat Received 0.07 Ml Of HA Filler, Which Was Injected Into The Lower Lip, Whereas Group I Served As Positive Control, Where The Animals Were Injected With 0.9 % Saline Into The Lower Rat?s Lip In The Same Way As Those Of Experimental Group.